This invention relates to murine monoclonal antibodies and particularly relates to production of unique monoclonal antibodies which specifically bind to terminal deoxynucleotidyl transferase (TdT) enzyme in lymphocyte cells of a variety of mammals, including humans.
Although TdT is found in a very small percentage of normal lymphoblasts, particularly in the early development of the immune system of vertebrates, elevated levels of TdT have been used in the diagnosis of human leukemias. TdT has become a valuable enzymatic marker for lymphoblastic neoplasms, such as acute lymphoblastic leukemia (ALL), chronic granulocytic leukemia (CGL) and lymphoblastic lymphoma (LL). Consequently, research has been conducted to develop methods for measurement of the frequency of lymphocytes which are positive for TdT in both normal and leukemic mammals. U.S. Pat. No. 4,307,189 describes a method for quantitative determination of TdT using labelled deoxynucleoside triphosphates which are converted by TdT to fluorescent or radioactive polydeoxynucleotides which may be quantified as a reflection of the amount of TdT originally present in the biological sample. However, this method does not employ monoclonal antibodies to TdT.
In studies published by C. Augl et al (Fed.Proc.42:2147 1983) (Abstract) the production of monoclonal antibodies to bovine TdT has been reported without description of detailed binding recognition of the antibodies. Immunochemical studies of TdT in a variety of mammals have demonstrated that peptides of this enzyme are immunologically related when probed with antiserum prepared to the degraded enzyme from bovine thymus as reported by F. J. Bollum (Journal of Biological Chemistry 256:8768, 1981).
In studies published by F. J. Bollum, et al. (Journal of Biological Chemistry 259: 5848 1984), the production of monoclonal antibodies to human TdT has been described. These anti-human monoclonal antibodies were widely variable in ability to recognize epitopes or determinants on TdT in human and calf cells.